Another west African border has been closed in an attempt to prevent Ebola's spread

The World Health Organization (WHO) on Wednesday reported 128 new Ebola cases and 56 deaths in West Africa in the two days to August 11, raising the death toll from the worst ever outbreak of the disease to 1,069.

Since the outbreak was identified in March, there have been a total of 1,975 confirmed, probable and suspected Ebola cases in Guinea, Liberia, Sierra Leone and Nigeria, the United Nations health agency said in a statement.

Governments have taken a range of measures to prevent the spread of Ebola across international borders. Ivory Coast on Monday banned air travelers from the three worst-hit countries, while Ghana on Tuesday postponed the start of the academic year for at least two weeks at universities and colleges to allow screening measures to be put in place.

'Nefarious Ebola'

Scientists studying the lethal Ebola virus say they have found how it blocks and disables the body's ability to battle infections in a discovery that should help the search for potential cures and vaccines.

A group of scientists in the United States found that Ebola carries a protein called VP24 that interferes with a molecule called interferon, which is vital to the immune response.

"One of the key reasons that Ebola virus is so deadly is because it disrupts the body's immune response to the infection," said Chris Basler of the Icahn School of Medicine at Mount Sinai, New York, who worked on the study.

"Figuring out how VP24 promotes this disruption will suggest new ways to defeat the virus."

The team, lead by Gaya Amarasinghe from Washington University School of Medicine, found that VP24 works by stopping something called "transcription factor STAT1" - which carries interferon's antiviral message - from entering the nucleus of a cell and initiating an immune response.

"This study shows just how nefarious the Ebola virus can be," said Ben Neuman, a virologist at Britain's university of Reading who was not directly involved in this study.

"Ebola virus carries a small tool that intercepts the cell's distress signals, and when this happens, it disables some of the most useful machinery that our bodies have for fighting Ebola. That leaves the body with only crude defenses that are less effective at stopping the virus, and end up causing much of the damage that can eventually lead to death."

There are no proven treatments or vaccines to prevent Ebola, although several biotech companies and research teams have potential drugs in development.

Amarasingh's team, whose work was published in the journal Cell on Wednesday, said understanding how Ebola disarms immune defenses will be crucial in the development of new treatments.

A World Health Organization-convened panel of experts said on Tuesday that patients infected with Ebola in the West African outbreak could be offered experimental drugs.

The WHO's panel of medical ethicists said several drugs had passed the laboratory and animal study phases of development and should be fast-tracked into clinical trials and made available for compassionate use.

Liberia said on Tuesday it would treat two infected doctors with the scarce experimental Ebola drug ZMapp, the first Africans to receive the treatment, while authorities in Spain said a 75-year-old priest had died of the disease.

Beth and Frank Seaton waited at O’Hare International Airport on Monday, anxious to greet their 23-year-old son, who is among hundreds of Peace Corps volunteers recalled from Western Africa because of the worst Ebola outbreak on record, which is centered in the region.

The use of an experimental drug to treat two Americans and a Spaniard diagnosed with Ebola is raising ethical questions about who gets first access to unproven new therapies. AP medical writer Lauran Neergaard takes a closer look.

The arrival of a man infected with Ebola virus in Lagos, Nigeria — Africa's largest city — last week was certainly an alarming development, but it's also in some ways a distraction. Nigeria has far more resources to throw at the problem than Guinea, Liberia and Sierra Leone....